Clean up and pop dead runspace when using 'attach'

[TylerLeonhardt]

Previously, when you used the attach launch config, if you killed the process that you were attaching to while PSES was attached to it, PSES would go into a bad state and hang forever.

This was because the Runspace wasn't getting cleaned up properly when the connection between the two processes broke.

This change checks for the bad runspace state, cleans up, and pops the bad runspace.

Here's what you see:

[DBG]: [Process:42420]: [Runspace1]: PS /Users/tyler/Downloads/anothertestfunc>> 

Command or script completed.
To end the debugging session type the 'Detach' command at the debugger prompt, or type 'Ctrl+C' otherwise.

Leaving debugged runspace on local machine Tylers-MacBook-Pro
The background process reported an error with the following message: "The named pipe target process has ended.".
At line:0 char:0
PS /Users/tyler/Downloads/anothertestfunc>

which is very consistent with what pwsh.exe shows when this happens.

[rjmholt]

👀 aha!

[TylerLeonhardt]

I definitely want @SeeminglyScience's green check on this

[rkeithhill]

LGTM but I don't know the "attach" part of the debugger code all that well.

[SeeminglyScience]

LGTM!